Intel 810 on-board video driver (for Windows 9x/ME) for use with several HP models including the Pavilion 7850.
This is driver version 4.11.01.2537 and was taken from a HP restore disk labeled: HP5012-0423
Unzip to temp folder, run setup.exe to install.
Note: I posted an older version (4.11.01.1321) of this driver on May 18, 2004. It's located here: http://members.driverguide.com/driver/detail.php?driverid=142414
And of course you can always go to the Intel website and get the latest 810 drivers.